JP4098193B2 - Slide bearing and rotating anode type X-ray tube - Google Patents

Description

  The present invention relates to a bearing and an X-ray tube using the bearing, and more particularly to a sliding bearing and a rotary anode X-ray tube using a liquid lubricant.

  In recent years, plain bearings are used in various scenes and various environments, and high performance is desired. For example, a sliding bearing used for a rotary anode X-ray tube is required to have a harsh use environment of high-speed rotation under vacuum and high reliability.

A conventional plain bearing has a groove that draws in a liquid lubricant during rotation, and has a plurality of bearing portions that fit into a cylindrical member, and a shaft that has a portion that has a smaller diameter than the bearing portions between adjacent bearing portions. Was used. (Patent Document 1). Such a portion having a smaller diameter than the bearing portion has a function of storing a liquid lubricant in order to prevent seizure of the bearing portion (Patent Document 2).
Japanese Patent No. 3139873 (FIG. 7) JP 2001-276034 A (page 8)

  However, the conventional sliding bearing has the following problems.

  That is, as shown in FIG. 7, when the space between the cylindrical member 101 and the shaft body 102 is sufficiently filled with the liquid lubricant 103, the bearing seizure can be prevented, but the liquid lubricant 103 and the shaft body 102 And between the liquid lubricant 103 and the rotating cylindrical member 101 are large, and frictional heat is generated. This is not a problem when the cylindrical member 101 rotates at a relatively low speed. However, when the cylindrical member 101 rotates at a very high speed, the generated heat reduces the viscosity of the liquid lubricant 103 and decreases the load capacity of the bearing.

  Further, considering the frictional heat between the liquid lubricant 103 and the rotating cylindrical member 101, a part of the space between the cylindrical member 101 and the shaft body 102 is covered with the liquid lubricant 103 as shown in FIG. 9, as shown in FIG. 9, the liquid lubricant 103 is supplied only to one bearing portion 104 side (right side in the drawing), and the other bearing portion 104 (left side in the drawing) is sufficiently liquid lubricated. There is a case where the agent 103 is not supplied, and there is a problem that sticking of the shaft cannot be prevented.

  The present invention has been made to solve the above-described problems, and provides a highly reliable slide bearing that has a small friction loss and can stably supply a liquid lubricant to the bearing even when rotated at high speed. The purpose is to do.

  It is another object of the present invention to provide a highly reliable rotary anode type X-ray tube that has a small friction loss even when the anode is rotated at high speed and can stably supply a liquid lubricant to the bearing portion.

  In order to achieve the above object, a plain bearing according to the present invention is provided with a cylindrical member, a shaft main body inserted into the cylindrical member, and a part of the shaft main body spaced apart from each other. A plurality of bearing portions that are rotatably fitted relative to each other, a liquid lubricant interposed between the cylindrical member and the bearing portion, and at least between the bearing portions of the shaft body. A diameter that is provided adjacent to each other, has a smaller diameter than the bearing portion, and a total volume of a space between the cylindrical member and a space between the bearing portion and the cylindrical member is smaller than a volume of the liquid lubricant. A first small-diameter portion having a length and a first small-diameter portion of the shaft main body, the first small-diameter portion being adjacent to the first small-diameter portion, having a smaller diameter than the first small-diameter portion, and the cylindrical member and the bearing portion being A second small diameter portion having a diameter and a length that do not come into contact with the liquid lubricant when rotating relatively; It is characterized by having.

  In order to achieve the above object, a rotating anode X-ray tube according to the present invention includes a cylindrical member, a shaft body that is inserted into the cylindrical member and rotatably supports the cylindrical member, and the cylinder. In a rotary anode type X-ray tube having a rotary anode attached to a cylindrical member and a vacuum vessel in which the cylindrical member and the rotary anode are housed, a part of the shaft body is provided apart from each other. A plurality of bearing portions that have grooves for drawing the liquid lubricant during rotation and that rotatably fit the cylindrical member, the liquid lubricant interposed between the cylindrical member and the bearing portion, Between at least the bearing portions of the shaft body, adjacent to the bearing portion, having a smaller diameter than the bottom of the groove, and a space between the cylindrical member and a space between the bearing portion and the cylindrical member. The total volume has a diameter and length that are smaller than the volume of the lubricant. A small-diameter portion, and a diameter that is provided adjacent to the first small-diameter portion of the shaft body, is smaller in diameter than the first small-diameter portion, and does not contact the liquid lubricant when the cylindrical member rotates. It has the 2nd small diameter part which has length, It is characterized by the above-mentioned.

  According to the present invention, even when the cylindrical member and the bearing portion are rotated at a relatively high speed, the friction loss is small, the liquid lubricant can be stably supplied to the bearing portion, and a highly reliable slide bearing is provided. Can be provided.

  Further, even when the anode is rotated at a high speed, the friction loss is small, and the liquid lubricant can be stably supplied to the bearing portion, so that a highly reliable rotary anode X-ray tube can be provided.

Embodiments of the present invention will be described below with reference to the drawings.

  Below, the Example of the rotating anode type | mold X-ray tube by this invention is described with reference to FIGS. FIG. 1 is a partially cutaway sectional view of an embodiment of a rotating anode X-ray tube according to the present invention.

  A fixed shaft 2 that is a shaft body is fixed inside a vacuum vessel (not shown) whose interior is kept in a vacuum. A rotating body 4, which is a cylindrical member to which the rotating anode 3 is attached, is fitted inside the vacuum vessel so as to be rotatable on the fixed shaft 2.

  Bearing parts 5 a and 5 b are provided apart from each other on a part of the fixed shaft 2. A liquid lubricant 6 is sealed in the space between the fixed shaft 2 and the rotating body 4. The liquid lubricant 6 is a liquid having high electrical conductivity and conductivity, such as a liquid metal, and electrically and thermally connects the fixed shaft 2 and the rotating body 4. By electrically connecting between the fixed shaft 2 and the rotating body 4, it is possible to energize the rotating anode 3 from the fixed shaft 2, and by fixing the heat between the fixed shaft 2 and the rotating body 4 Heat can be radiated from the shaft 2 to the rotating anode 3.

  A dynamic pressure groove 7 is processed in the bearing portions 5a and 5b, and the liquid lubricant 6 is drawn into the bearing portions 5a and 5b when the rotating body 4 rotates.

1st small diameter parts 8 and 8 are provided in the adjacent part by the side of the bearing part 5b of the bearing part 5a, and the adjacent part by the side of the bearing part 5a of the bearing part 5b. The diameters and lengths of the first small diameter portions 8 and 8 are smaller than the bottom of the dynamic pressure groove 7, the space between the first small diameter portions 8 and 8 and the rotating body 4, and the bearing portion 5.
The total volume of the spaces a and 5b and the rotating body 4 is set to be smaller than the volume of the liquid lubricant 6.

  Furthermore, a second small diameter portion 9 is provided at a position sandwiched between the first small diameter portions 8 and 8 of the fixed shaft 2. The diameter and length of the second small-diameter portion 9 are smaller than those of the first small-diameter portions 8 and 8. When the rotating body 4 does not rotate, the liquid lubricant 6 is accumulated, and when the rotating body 4 rotates. The second small diameter portion 9 and the lubricant 6 are in contact with each other in a state in which the liquid lubricant 6 is filled in the gaps between the bearing portions 5a and 5b and the first small diameter portions 8 and 8 and the rotating body 4. Set to not.

  A stator 10 having an electromagnetic coil is disposed outside the rotating body 4 to generate a rotating magnetic field, and the rotating body 4 and the rotating anode 3 are rotated at high speed.

  In order to explain the operation mechanism of the sliding bearing of the rotating anode type X-ray tube according to the present embodiment, FIGS. 2 (a) and 2 (b) to 5 show an operation model of the bearing portion. Here, the first small diameter portion 8 is provided at a total of four locations on both sides of the bearing portions 5a and 5b. In addition, in FIG. 1, since the bearing parts 5a and 5b are located in the both ends of the inner wall 11 of the rotary body 4, the 1st small diameter part 8 of the outer two places of the bearing parts 5a and 5b is unnecessary, and the bearing part 5a. 5b is disposed only at two locations inside.

  2A is a diagram showing the inside of the sliding bearing when the rotating body 4 is stopped, and FIG. 2B is a diagram showing the inside of the sliding bearing when the rotating body 4 is rotating. As shown in FIG. 2A, when the rotating body 4 is stopped, the liquid lubricant 6 accumulated under the bearing portions 5a and 5b, the first small diameter portion, and the second small diameter portion in the rotating body 4 due to gravity. The centrifugal force acts with the rotation of the rotating body 4 and adheres to the entire inner wall of the rotating body 4 as shown in FIG.

  FIG. 3 is an enlarged view showing the inside of the plain bearing during rotation, particularly the vicinity of the second small diameter portion 9. When the liquid lubricant 6 rotates together with the rotating body 4, centrifugal force acts on the liquid lubricant 6, and the liquid lubricant 6 and the second small diameter portion 9 do not come into contact with each other. The friction loss between the rotating body 4 and the rotating body 4 and the friction loss between the liquid lubricant 6 and the fixed shaft 2 do not occur. In addition to the dynamic pressure generated by the dynamic pressure groove 7, the fluid pressure generated from the centrifugal force acting on the surplus portion 12 of the liquid lubricant 6 improves the load capacity of the bearing.

  FIG. 4 is an enlarged view of the inside of the sliding bearing during rotation, particularly the vicinity of the second small diameter portion 9 when the amount of the liquid lubricant 6 is larger than that in FIG. 3 due to variations in manufacturing and environmental changes. FIG. Since there is a margin until the liquid lubricant 6 and the second small diameter portion 9 come into contact with each other, no friction loss occurs in the second small diameter portion 9 even if the liquid level of the liquid lubricant 6 increases.

  FIG. 5 shows an enlarged view of the inside of the sliding bearing during rotation, particularly the vicinity of the second small diameter portion 9 when the amount of the liquid lubricant 6 is smaller than that of FIG. FIG. A space 13 between the liquid lubricant 6 and the second small-diameter portion 9 becomes large, and the inner wall 11 of the rotating body 4 is exposed. However, unlike the conventional plain bearing shown in FIG. 9, the exposure of the inner wall 11 occurs first from the second small diameter portion 9 portion, so that there is a margin until the exposure of the inner wall 11 reaches the bearing portions 5a and 5b.

  According to the rotary anode type X-ray tube configured as described above, high-speed rotation is possible with low friction loss, and the liquid lubricant 6 is stably supplied, so that it has high reliability.

In this embodiment, the cylindrical rotating body 4 is used as the cylindrical member. However, the cylindrical member may be, for example, a two-piece member, a through hole provided in the base plate, a thrust direction bearing mechanism, and the like. What is necessary is just to be able to fix so that rotation is possible. In this embodiment, the shaft main body is the fixed side and the cylindrical member is the rotating side, but the cylindrical member may be the fixed side and the shaft main body may be the rotating side.

  In this embodiment, the hydrodynamic fluid bearing having the dynamic pressure groove 7 is taken as an example, but it goes without saying that a plain bearing without the dynamic pressure groove 7 may be used.

  Hereinafter, an embodiment in which the sliding bearing using the present invention is applied to a flywheel for an artificial satellite will be described with reference to FIG. The same parts as those of the first embodiment shown in FIGS. 2 to 5 are denoted by the same reference numerals, and the description thereof is omitted.

  A rotating body 4 is rotatably mounted inside a housing 20 having a fixed shaft 2. A flywheel mass 22 having a motor rotor 21 is fixed to the rotating body 4. The rotating body 4 is held in the radial direction by the bearing portions 5a and 5b and in the thrust direction by the thrust bearing portion 23, thereby enabling the housing 20 and the flywheel mass 22 to rotate relatively smoothly. The inside of the rotating body 4 is sealed with a packing 24 and supplied with a liquid lubricant 6 having a low saturated vapor pressure, for example, a liquid metal.

  According to the above-described flywheel for an artificial satellite, high-speed rotation is possible with low friction loss, and the liquid lubricant 6 is stably supplied, so that it has high reliability. Further, since the artificial satellite is used in a vacuum, the liquid lubricant 6 evaporates if the airtight state of the packing 24 is not maintained. By using the liquid lubricant 6 having a low saturated vapor pressure, the pressure inside the rotating body 4 can be lowered, the airtightness required for the packing 24 is relaxed, and the reliability can be improved. .

Internal view of an embodiment of a rotating anode X-ray tube according to the present invention The figure which showed the operation | movement model of the bearing part of the rotating anode type X-ray tube by this invention The enlarged view of the 2nd small diameter part which showed the operation | movement model of the bearing part of the rotating anode type | mold X-ray tube by this invention The enlarged view of the 2nd small diameter part which showed the operation model in case the liquid level of the liquid lubricant of the bearing part of the rotating anode type X-ray tube by this invention is high The enlarged view of the 2nd small diameter part which showed the operation | movement model when the liquid level of the liquid lubricant of the bearing part of the rotating anode type X-ray tube by this invention is low The figure which showed the Example of the flywheel for artificial satellites by this invention The figure which showed the operation model of the bearing part when the liquid level of the liquid lubricant of the conventional rotary anode type X-ray tube is high The figure which showed the operation model of the bearing part when the liquid level of the liquid lubricant of the conventional rotary anode type X-ray tube is low The figure which showed the operation model of the bearing part when the liquid level of the liquid lubricant of the conventional rotary anode type X-ray tube is low and the liquid lubricant is not sufficiently supplied to the bearing part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Fixed shaft 3 Rotating anode 4 Rotating body 5a, 5b Bearing part 6 Liquid lubricant 7 Dynamic pressure groove 8 1st small diameter part 9 2nd small diameter part 10 Stator 11 Inner wall 12 Surplus part 13 Space 20 Housing 21 Motor rotor 22 Flywheel Mass 23 Thrust bearing portion 24 Packing 101 Tubular member 102 Shaft body 103 Liquid lubricant 104 Bearing portion

Claims (3)

A tubular member;
A shaft body inserted into the tubular member;
A plurality of bearing portions which are provided apart from each other in a part of the shaft main body and which are rotatably fitted to the cylindrical member;
A liquid lubricant interposed between the cylindrical member and the bearing portion;
Provided adjacent to the bearing portion between at least the bearing portions of the shaft main body, having a smaller diameter than the bearing portion, and a space between the cylindrical member and a space between the bearing portion and the cylindrical member. A first small diameter portion having a diameter and a length, the total volume of which is smaller than the volume of the liquid lubricant;
The liquid lubricant is provided adjacent to the first small-diameter portion of the shaft main body, and has a smaller diameter than the first small-diameter portion, and the cylindrical member and the bearing portion rotate relatively. A slide bearing comprising a second small diameter portion having a diameter and a length that do not contact each other. A tubular member;
A shaft body inserted into the tubular member and rotatably supporting the tubular member;
A rotating anode attached to the tubular member;
In the rotary anode type X-ray tube having the cylindrical member and the vacuum container containing the rotary anode therein,
A plurality of bearing portions that are provided apart from each other in a part of the shaft main body, have grooves into which a liquid lubricant is drawn during rotation, and fit the cylindrical member rotatably;
A liquid lubricant interposed between the cylindrical member and the bearing portion;
The shaft body is provided between at least the bearing portions and adjacent to the bearing portion, has a smaller diameter than the bottom of the groove, and a space between the cylindrical member and a space between the bearing portion and the cylindrical member. A first small-diameter portion having a diameter and length smaller than the volume of the lubricant,
A second portion provided adjacent to the first small diameter portion of the shaft body, having a diameter and a length that is smaller than the first small diameter portion and does not contact the liquid lubricant when the cylindrical member rotates. A rotary anode X-ray tube characterized by having a small-diameter portion. The rotary anode type X-ray tube according to claim 2 , wherein the liquid lubricant is a liquid metal.

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